# Layered Context Architecture A layered context architecture keeps several sources of meaning distinct while composing them for a task: system rules, organization or account rules, project instructions, document content, retrieved records, memory, and runtime state. XDO's set/program/global hierarchy and its proposed run/document/account/system scopes map naturally onto this modern vocabulary. The correspondence is architectural; it does not imply that the historical runtime used a language model. Related: [[wiki/Context Engineering|Context Engineering]], [[wiki/Hierarchical Instruction Files|Hierarchical Instruction Files]], [[wiki/Agentic Memory|Agentic Memory]], [[wiki/Metadata Grounding|Metadata Grounding]]. Sources: [OpenAI — Inside our in-house data agent](https://openai.com/index/inside-our-in-house-data-agent/), [Anthropic — Claude Code memory](https://docs.anthropic.com/en/docs/claude-code/memory)